This invention relates to the field of intravascular catheters, and more particularly to a catheter with a lubricious catheter shaft and a method of manufacture thereof. In percutaneous transluminal coronary angioplasty (PTCA) a balloon catheter is used to restore free flow in a clogged coronary vessel. The catheter is maneuvered through the patient's tortuous anatomy and into the patient's coronary anatomy until the balloon is properly positioned across the stenosis to be dilated. Once properly positioned, the balloon is inflated with liquid one or more times to a predetermined size at relatively high pressures (e.g. greater than 4 atm) to reopen the coronary passageway. After the balloon is finally deflated, blood flow resumes through the dilated artery and the balloon catheter can be removed therefrom.
Balloon catheters generally comprise an elongated shaft with an inflatable balloon on the distal end of the shaft. An inflation lumen extending within the shaft is used to deliver inflation fluid to the balloon interior. In over the wire or rapid exchange designs, a guidewire is slidably received within a guidewire lumen extending at least within a distal section of the catheter.
A lubricious coating is typically provided on the outer surface of the catheter shaft to facilitate the movement of the catheter within the patient's body lumen. Additionally, a lubricious coating may be provided on an inner surface of the shaft which defines the guidewire lumen, to facilitate the movement of a guidewire therein. The lubricious coatings generally comprise silicone, polymeric materials, or hydrophilic compounds which become lubricious after absorbing water. However, a lubricious coating with high lubricity may often have poor adhesion to the catheter shaft surface. In addition to coatings which provide lubricity, catheter shafts may be formed from a hydrophilic polymeric blend. However, one challenge has been providing high lubricity without a loss of other catheter shaft characteristics such as low profile, strength, flexibility, and ease of manufacture.
Therefore, what has been needed is a balloon catheter having a lubricious shaft with improved shaft performance characteristics, which retains it's lubricity after repeated use, and which provides improved ease of manufacture. The present invention satisfies these and other needs.